1. Field of the Invention
The invention relates to novel alkaline proteases derived from a new species of the genus Bacillus and their derivatives. The invention relates also to a new bacterium producing this alkaline protease and also to derivatives of this bacterium. The invention concerns also a process for the production of this alkaline protease which comprises cultivating the new bacterium. The invention concerns the uses of this alkaline protease, a detergent composition containing said alkaline protease and a method for removing protein stains from cloth.
2. Discussion of Related Art
Bacterial proteases which have the ability of degrading proteins at pH levels above 9 and higher have been known for some time. These proteases are suitable for inclusion in detergent formulation due to their protein degrading function maintaining its activity at the relatively high pH levels typically employed in detergent cleaning operations.
Among the known high alkaline proteases are those disclosed by Takashi in published European Patent Application 0204342 which claims an alkaline protease produced by a microorganism belonging to the genus Bacillus which organism exhibits certain characteristics and the alkaline protease produced thereby.
In the article The Journal of Biological Chemistry, 1968, 243, n.degree. 9, p. 2184 the complete amino acid sequence of Subtilisin Carlsberg is described.
U.S. Pat. No. 4,052,262 to Horikoshi et al. claims a process for preparing an alkaline protease which involves the cultivation of a bacterium identified as Bacillus sp. No. 221 (ATCC 21522) in a suitable nutrient growth medium.
Ichishima et al. claim an alkaline protease identified as API-21 and characterized by certain physicochemical properties in U.S. Pat. No. 4,480,037. This protease is obtained by the cultivation which the patentees characterize as Bacillus sp. N.degree. NKS-21.
In U.S. Pat. No. 3,723,250 Aunstrup et al. disclose a method for preparing high alkaline proteases, particularly those having optimal proteolytic activity at a pH value above about 9 and which retain at least 80% of their maximum proteolytic value at pH 12, by cultivation of certain bacteria from the genus Bacillus.
In U.S. Pat. No. 4,002,572 Nijenhuis discloses Bacillus strain "PB 92" and claims the use of this strain in the production of an enzyme having high proteolytic activity in alkaline media.
Aunstrup et al. claim a method for the production of an alkaline proteolytic enzyme which involves the submerged cultivation of the microorganism designated as B. firmus, strain NRS 783 in U.S. Pat. No. 3,827,938.
U.S. Pat. No. 3,674,643 to Aunstrup et al. claims a method for preparing a proteolytic enzyme by cultivating B. alcalophilus Vedder in a suitable nutrient medium at a pH between 7.5 and 11.